Species richness of arbuscular mycorrhizal fungi in forests with Araucaria in Southern Brazil

This study aimed to characterize species richness of arbuscular mycorrhizal fungi (AMF) in three distinct forests with Araucaria angustifolia (native forest, reforestation with A. angustifolia and plantation with Pinus taeda) in the "Floresta Nacional de São Francisco de Paula", State of Rio Grande do Sul, also accounting for seasonal variation. Six soil samples from each forest were collected from Araucaria angustifolia rhizosphere in four seasons during a one-year period, for identification of the AMF species. Spores were extracted by wet-sieving followed by centrifugation in water and 50% sucrose solution. The greatest richness (16 species) was found in the Araucaria reforestation and the lowest in the native forest (eight species). The season with higher species richness was different in each site. The most representative genera in all forests were Acaulospora and Glomus. Historical aspects and plant species composition can account for some of the differences among sites